Method for using expandable tubulars

ABSTRACT

An improved method for completing wells, such as hydrocarbon wells, is provided. In one aspect, methods are provided for deploying an expandable tubular, such as an expandable sand screen, in a hydrocarbon well. According to methods of the present invention, a sand screen is lowered into a wellbore. Thereafter, cement is injected into the wellbore so as to place a column of cement in the annular region between the tubular and the surrounding formation. The cement is then treated so as to imbue greater permeability and/or porosity characteristics. The cement serves to reinforce the sand screen, providing it with both improved physical strength and improved sand filtering ability. At the same time, the sand screen serves to reinforce and strengthen the cement sheath placed in the wellbore.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to methods for completing wells,such as hydrocarbon and water wells. More specifically, the presentinvention provides methods for deploying an expandable tubular in ahydrocarbon well. More particularly still, methods are provided forplacing an expandable perforated tubular, such as a sand screen, withina wellbore having a permeable cement.

[0003] 2. Description of Related Art

[0004] Hydrocarbon wells are typically formed with a central wellborethat is supported by steel casing. The steel casing lines the boreholeformed in the earth during the drilling process. This creates an annulararea between the casing and the borehole, which is filled with cement tofurther support and form the wellbore.

[0005] Some wells are produced by perforating the casing of the wellboreat selected depths where hydrocarbons are found. Hydrocarbons migratefrom the formation, through the perforations, and into the casedwellbore. In some instances, a lower portion of a wellbore is left open,that is, it is not lined with casing. This is known as an open holecompletion. In that instance, hydrocarbons in an adjacent earthformation migrate directly into the wellbore where they are subsequentlyraised to the surface, typically through an artificial lift system.

[0006] Open hole completions carry the potential of higher productionthan cased hole completions. Open hole completions are frequentlyutilized in connection with horizontally drilled boreholes. However,open hole completions present various risks concerning the integrity ofthe open wellbore. In that respect, an open hole leaves aggregatematerial, including sand, free to invade the wellbore. Sand productioncan result in premature failure of artificial lift and other downholeand surface equipment. Sand can build up in the borehole and tubing toobstruct fluid flow. Particles can compact and erode surroundingformations to cause liner and casing failures. In addition, producedsand becomes difficult to handle and dispose of at the surface.Ultimately, open holes carry the risk of complete collapse of theformation into the wellbore.

[0007] Heretofore, gravel packs have been utilized in wells to preservethe integrity of the formed borehole, and to prevent the production offormation sand. In gravel packing operations, a pack of gravel, e.g.,graded sand, is placed in the annulus between a perforated or slottedliner or screen and the walls of the wellbore in the producing interval.The resulting structure provides a barrier to migrating sand from theproducing formation while allowing the flow of produced fluids.

[0008] While gravel packs inhibit the production of sand with formationfluids, they often fail and require replacement due, for example, to thedeterioration of the perforated or slotted liner or screen as a resultof corrosion or the like. In addition, the initial installation of agravel pack adds considerable expense to the cost of completing a well.The removal and replacement of a failed gravel pack is even more costly.

[0009] To better control particle flow from unconsolidated formations,an improved form of well screen has been recently developed. The wellscreen is known as an expandable sand screen, or “ESS® screen.” The ESS®system is run into the wellbore at the lower end of a liner string andis expanded into engagement with the surrounding formation, therebyobviating the need for a separate gravel pack. In general, the ESS®system is constructed from three composite layers, including a slottedbase pipe, a protective, perforated outer shroud, and an intermediatefilter media. The filter media allows hydrocarbons to invade thewellbore, but filters sand and other unwanted particles from entering.Both the base pipe and the outer shroud are expandable, with the wovenfilter being arranged over the base pipe in sheets that partially coverone another and slide across one another as the sand screen is expanded.

[0010]FIG. 1 presents a section view showing a wellbore 40. The wellbore40 is lined with a string of casing 42. The casing 42 separates theinterior of the wellbore 40 from the surrounding earth formation 48. Anannular area is left between the casing 42 and the earth formation 48and is filled with cement 46, as is typical in a well completion.Extending downward below the cased portion of the wellbore 40 is an openhole portion 50. The earth formation 48 forms the wall of the wellborefor the open hole portion 50.

[0011] Disposed in the open hole portion 50 of the wellbore 40 is anexpandable tubular 20. In the view of FIG. 1, the tubular 20 representsa sand screen 20, such as Weatherford's ESS® sand screen. The expandablesand screen 20 is hung within the wellbore 40 from a hanging apparatus32. In some instances, the hanging apparatus 32 is a packer. In thedepiction of FIG. 1, the hanging apparatus 32 is a liner 30 and linerhanger 32.

[0012] A production tubular 44 is also seen placed in the wellbore 40 ofFIG. 1. The production tubular 44 extends from the surface and into atop portion of the liner 30. A packer 34 is employed to seal the annulusbetween the production tubular 44 and the liner 30.

[0013] Also depicted in FIG. 1 is an instrumentation line 62. Theoptional instrumentation line 62 runs within an encapsulation 12 fromthe earth surface (not shown) along the production tubular 44. Theencapsulation 12 is secured to the production tubular 44 by clamps,shown schematically at 18. Clamps 18 are typically secured to theproduction tubular 44 approximately every ten meters. The encapsulation12 passes through the liner hanger 32 (or utilized hanging apparatus),and extends downward to the top 21 of the sand screen 20. In thearrangement shown in FIG. 1, the instrumentation line 62 enters a recess(shown at 10 in FIG. 2) in the outer diameter of the ESS® 20.Arrangements for the recess 10 are described more fully in the pendingapplication entitled “Profiled Recess for Instrumented ExpandableComponents,” having Ser. No. 09/964,034, which is incorporated herein inits entirety, by reference. However, the instrumentation line 62 mayalso be housed in a specially profiled encapsulation around the ESS® 20which contains arcuate walls. Arrangements for the encapsulation aredescribed more fully in the pending application entitled “ProfiledEncapsulation for Use With Expandable Sand Screen,” having Ser. No.09/964,160, which is also incorporated herein in its entirety, byreference.

[0014]FIG. 2 presents a cross-section of a sand screen 20′ within anopen hole completion wellbore 50′. The sand screen 20′ is seen within asurrounding formation 48. Three layers of the sand screen 20′ are shown,representing a base pipe 22, a protective outer shroud 26, and anintermediate filter media 24. Slots 23 are seen within the base pipe 22and the shroud 26. A recess 10 is seen within the outer shroud 26 forreceiving a pair of instrumentation lines 62. In this arrangement, theinstrumentation lines 62 are housed within tubular casings 60.

[0015] In FIGS. 1 and 2, the sand screens 20, 20′ are shown in theirrun-in positions. However, the sand screens 20, 20′ are configured to beexpandable. In this manner, the sand screens 20, 20′ are expandeddownhole against the adjacent formation 48 in order to preserve theintegrity of the formation 48 during production. This step is presentedin FIG. 3, which presents the open wellbore 50 with the sand screen 20having been expanded.

[0016]FIG. 4 presents the sand screen 20′ of FIG. 2, in its expandedstate. Here, the sand screen 20′ has been expanded into radialfrictional engagement with the surrounding formation 48. Expansion ofthe sand screen 20′ obviates the need for a gravel pack, and allows fora larger i.d. within the production zone. A more particular descriptionof an expandable sand screen is described in U.S. Pat. No. 5,901,789,which is incorporated by reference herein in its entirety.

[0017] The expandable sand screens 20, 20′ are expanded by an expandertool 200. An example of an expander tool 200 as may be used to expand adownhole tubular such as sand screen is seen in FIG. 5. FIG. 5 presentsa perspective view of an expander tool 200. The expander tool 200 firstcomprises a conical portion, or “cone” 210. The cone 210 is urgedthrough the inner bore of the sand screen 20 by pushing down or pullingup on a connected working string (not shown), or by otherwisetranslating the expander tool 200 such as through a downhole translationmechanism. The cone 210 has an outer diameter that is greater than theinner diameter of the sand screen 20. As the cone is urged through thesand screen 20, both the inner and outer diameters of the sand screen 20are expanded.

[0018] The expander tool 200 of FIG. 5 also comprises a hydraulicallyactuated tool portion 220. The hydraulically actuated portion 220defines a body 222 having a plurality of radially outward extendingroller members 216. The roller members 216 are urged outwardly away fromthe tool body 222 in response to fluid pressure applied within theperforated inner mandrel of the tool 200.

[0019] When it is desired to expand a tubular downhole, the expandertool 200 is translated axially (such as by raising and/or lowering theworking string from the surface) along a desired length. Where a sandscreen 20 is used as the expandable tubular, the expander tool 200 istranslated along the length of the sand screen 20 in order to expand theinner and outer diameters of the screen 20. The sand screen components22, 26 are stretched past their elastic limit, thereby increasing theouter diameter of the sand screen 20. In this way, the screen walls areplaced closely adjacent to the borehole wall in full compliance, even inan irregular borehole.

[0020] In order to obtain a radial expansion of a downhole tubular 20,the expander tool 200 may also be rotated. This may be accomplished invarious ways, such as by rotating the working string from the surface orby employing a downhole motor.

[0021] Using expander means such as tool 200, an expandable tubular 20is subjected to outwardly radial forces that expand the diameter of thesurrounding tubular 20. It is understood, however, that other types ofexpander tools exist for expanding an elongated tubular body downhole.The description of the expander tool 200 shown in FIG. 5 is not intendedto be a limitation as to how a sand screen or other expandable tubularmight be expanded in the methods of the present invention.

[0022] The sand screens 20, 20′ of FIGS. 1 and 2, while representing animprovement over prior gravel pack and sand screen devices, neverthelesshave limitations. For example, the ESS® itself (if misapplied) issusceptible to the detrimental effects of fluid and sand particlesflowing therethrough, including erosion, corrosion, and abrasion. Inaddition, the ESS® filter media 24 can become plugged with finergranular and clay particles if not correctly installed in contact withthe borehole wall 48, i.e., in “compliant expansion.” Finally, thelayers 22, 24, 26 of the ESS® have limitations in terms of physicalstrength. In certain extreme cases where producing formations andwellbores are unstable or irregular and difficult to obtain a competentgravel pack, it may also be difficult to obtain fully compliantexpandable screen installation. Therefore, it is desirable to supportthe ESS® system by injecting a thin cement column therearound. Thecement sheath can cater for very large dimensional irregularities and,coupled with mechanical tubular support, can further stabilize theformation/wellbore.

[0023] It is known to employ a column of porous and permeable cement asa substitute for a gravel pack. U.S. Pat. No. 6,390,195 issued to Nguyenin May of 2002 provides a method of forming a permeable cement sandscreen in a wellbore adjacent to a fluid producing zone. Similarly, U.S.Pat. Nos. 6,202,751 and 6,364,945, issued in 2001 and 2002 respectively,to Chatterji, present compositions for such a permeable cement sandscreen. The method of the '195 patent includes the use of a perforatedpipe within the wellbore at the producing zone. However, the pipe is notexpanded, nor is it slotted. The use of slotted expandable pipe affordsa significantly improved inflow area to the completion which aids fluidflow and thereby increases the economic benefit to the installation.

[0024] Accordingly, a need exists for a method for completing a wellborewherein an expandable sand screen is placed adjacent a production zone,and is assisted by a column of permeable granular material.

SUMMARY OF THE INVENTION

[0025] An improved method for completing wells, such as hydrocarbon andwater wells, is provided. According to methods of the present invention,an expandable, perforated tubular, such as a sand screen or apre-slotted liner, is lowered into a wellbore. Thereafter, cement isinjected into the wellbore so as to place a column of cement in theannular region between the tubular and the surrounding formation.

[0026] In one aspect, the expandable tubular, e.g., sand screen, isexpanded before cement is injected into the annular region. The tubularis not expanded into complete frictional engagement with the surroundingformation, but an annular region is preserved. In another aspect, thecement is injected into the annular region before the tubular isexpanded. In this arrangement, the expansion operation is conductedbefore the cement is completely cured. In either aspect, a thin cylinderof cement is formed around the expandable tubular.

[0027] After the sand screen has been expanded and the cement injected,the cement is cleaned out of the bore of the sand screen. In one aspect,this is accomplished by drilling the cement out of the bore. In anotheraspect, a treating fluid, e.g., an acid, is injected into the wellboreat the depth of the sand screen after the cement has been drilled out ofthe sand screen. The treating fluid imbues permeability and/or porositycharacteristics to the cement, thereby permitting the flow ofhydrocarbons therethrough.

[0028] The cement serves to reinforce the expandable tubular, providingit with both improved physical strength and improved sand filteringability. At the same time, the sand screen (or other expandable tubular)serves to reinforce the cement after it has cured. The use of cement inconnection with the deployment of an expandable sand screen may be donein either an open hole completion, or in a cased wellbore. The use ofcement in connection with an expandable sand screen may also be used torepair failed sand control completions within a wellbore.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] So that the manner in which the above recited features of thepresent invention, and other features contemplated and claimed herein,are attained and can be understood, a more particular description of theinvention, briefly summarized above, may be had by reference to theappended drawings (FIGS. 7A through 8F). It is to be noted, however,that the drawings illustrate only typical embodiments of this inventionand are therefore not to be considered limiting of its scope, for theinvention may admit to other equally effective embodiments.

[0030]FIG. 1 presents a cross-sectional view of a wellbore. Anexpandable sand screen has been deployed in the wellbore. The sandscreen has not yet been expanded.

[0031]FIG. 2 provides a cross-sectional view of an expandable sandscreen. The sand screen is shown within an open hole, in its unexpandedstate.

[0032]FIG. 3 presents the wellbore of FIG. 1, with the sand screenhaving been expanded into contact with the surrounding earth formation.

[0033]FIG. 4 demonstrates a cross-sectional view of an expandable sandscreen, with the sand screen having been radially expanded.

[0034]FIG. 5 provides a perspective view of an expander tool as might beused in the methods of the present invention.

[0035]FIG. 6A presents a cut-away view of an expandable sand screen asmight be used in the methods of the present invention. The sand screenhas not been expanded. Parts of the sand screen are exploded apart forclarity.

[0036]FIG. 6B presents the expandable sand screen of FIG. 6A,incorporated into a run-in string and in series with completion tools.Here, the sand screen has been expanded by a tapered cone.

[0037]FIGS. 7A-7E present steps for deploying a sand screen inaccordance with one of the methods of the present invention. In each ofthese drawings, a cross-sectional view of a sand screen within awellbore is provided.

[0038] In FIG. 7A, the sand screen has been run into the wellbore. Thesand screen has not yet been expanded.

[0039] In FIG. 7B, the sand screen is being radially expanded along itslength. In this arrangement, a tapered cone is being used as theexpander tool.

[0040]FIG. 7C shows cement being squeezed up the annular region definedby the sand screen and the surrounding formation.

[0041] The expanded sand screen is again shown in the view of FIG. 7D.Here, the expander tool has been removed from the wellbore, and theworking string has been reintroduced into the wellbore with a drill bitat the lower end. The drill bit is shown drilling out cement depositedor left inside the sand screen.

[0042]FIG. 7E presents the wellbore of FIG. 7A having been completed.The drill bit is removed from the wellbore, and fluids are beingproduced through the cement column and through the sand screen. Arrowsdepict the flow of fluids, e.g., hydrocarbons, into the wellbore.

[0043]FIGS. 8A-8E present steps for deploying a sand screen inaccordance with another of the methods of the present invention. In eachof these drawings, a cross-sectional view of a wellbore is again seen.Here, the wellbore is cased.

[0044] In FIG. 8A, a string of casing is shown within the wellbore. Thecasing string has been perforated.

[0045]FIG. 8B demonstrates a sand screen being run into the wellbore ofFIG. 8A. The sand screen is located at a depth that traverses theperforated zone. In this arrangement, a mule shoe at the lower end ofthe sand screen rests at the bottom of the borehole. An expander tool istemporarily attached at the top end of the sand screen. The sand screenhas not yet been expanded

[0046] In FIG. 8C, the sand screen is being radially expanded along itslength. In this arrangement, a tapered cone is again being used as theexpander tool. A packer is seen set above the sand screen.

[0047]FIG. 8D shows cement being squeezed up the annular region definedby the sand screen and the surrounding formation.

[0048] The expanded sand screen is shown in the view of FIG. 8E. Thecone has been removed from the wellbore, and the working string has beenreintroduced into the wellbore, with a drill bit at the lower end. Thedrill bit is shown drilling out cement inside the sand screen.

[0049]FIG. 8F presents the wellbore of FIG. 8B having been completed.The drill bit is removed from the wellbore, and fluids are beingproduced through the cement column and through the sand screen. Arrowsdepict the flow of fluids, e.g., hydrocarbons, into the wellbore.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0050]FIG. 6A presents a more detailed view of an expandable sand screen100 as might be used in the methods of the present invention. FIG. 6A isa cut-away view taken along the longitudinal axis of the tool 100. Theouter protective shroud 126 is seen around the sand screen 100, whilethe inner base pipe 122 is seen along the cut-away portion of thedrawing. A filtration media 124 is disposed between the outer shroud 126and the base pipe 122. In the view of FIG. 6A, the filtration media 124is seen only through the slotted outer shroud 126.

[0051] In the arrangement shown in FIG. 6A, the expandable sand screen100 defines three distinct portions: (1) a top connector 110; (2) one ormore expandable sand screen joints 120; and (3) a bottom connector 130.The top connector 110, the sand screen joint 120, and the bottomconnector 130 are exploded apart for clarity.

[0052] First, the top connector 110 serves to connect the sand screenjoints 120 to a working string (such as the drill string shown at 70 inFIGS. 7A-7E). In some instances, a blank pipe (not shown) is placedbetween the top connector 110 and the working string. The top connector110 includes an upward stub Acme box connection member 112 at its topend. The top connector 110 also has a male threaded connection member114 at its lower end. Intermediate the upper 112 and lower 114connectors, the top connector 110 has a body 116 having a pre-formedshape. The body 126 is configured to receive and house an expander tool,such as tool 200 shown in FIG. 5, during run-in.

[0053] Before expansion operations are conducted, a suitable sizedexpander tool 200 can be installed into the top connector 100 at the jobsite. To retain the expander tool 200 in position, shear screws (notshown) are installed through the expander tool's body 202. Thus, theexpander tool 200 is releasably connected to the top connector 100.

[0054] Second, one or more sand screen joints 120 are provided. ESS®joints are typically provided in 38 foot lengths. As noted, the ESS®joints 120 are comprised of three layers, to wit, a slotted steel tubeknown as a “base pipe” 122, overlapping layers of filtering membrane,i.e., “an intermediate filter media” 124, and a pre-slotted steel plate126 wrapped around the base pipe 122 and the filter media 124. Thefilter media 124 allows hydrocarbons to invade the wellbore, but filterssand and other unwanted particles from entering.

[0055] The sand screen joints 120 are configured to be expandable.Expansion is achieved either by using a compliant expander tool, bypassing a tapered cone through the inside of the joint 120, or by usingan expander tool that incorporates both features, such as tool 200 shownin FIG. 5. During the expansion process, both inner 122 and outer 126layers of the joints 120 are plastically deformed to achieve the desireddimension. The overlapping filter membranes 124 slide over one anotherto accommodate the increase in diameter.

[0056] Third, a bottom connector 130 is provided in the ESS® 100. Thebottom connector 130 has a top end 132 that connects to the bottom ofthe sand screen joint 120. The bottom connector 130 provides a positivelocation for receiving the expander tool 200 after the expansion processis completed. In one arrangement, the expander tool 200 remains in thewellbore after the expansion process is completed, with the workingstring being detachable from the expander tool 200. In one aspect, thebottom connector 130 connects at a lower end 134 to a shoe assembly(seen at 180 in FIG. 6B).

[0057] In operation, the sand screen 100 is run into a wellbore at theend of a working string. FIG. 6B presents the expandable sand screen 100of FIG. 6A, incorporated into a run-in string 70, and in series withcompletion tools. The completion tools include a hanger 140, a packer150, and a shoe assembly 180. The hanger 140 includes slip members 144having wickers for frictionally engaging a surrounding casing string(not shown in FIG. 6B). The packer 150 includes a sealing element 154for sealing engaging the surrounding wellbore once the packer 150 isset. FIG. 6B also shows in somewhat schematic fashion, a tapered cone210 releasably held within the sand screen 100. Here, the sand screen100 has been expanded along its length. Note again, though, that themethods of the present invention are not limited by the type of expandertool used for the expansion operation.

[0058] In some instances, the sand screen 100 is deployed in a wellborehaving an open hole completion. FIGS. 7A-7E present steps for deployinga sand screen 100 in accordance with one of the methods of the presentinvention. In each of these drawings, a cross-sectional view of the sandscreen 100 within an open hole wellbore 40 is provided. Thus, thewellbore 40 has an open hole portion 50. It is also understood that thesand screen 100 shown in FIGS. 7A-7E is exemplary. The present methodsare equally applicable for other expandable tubulars, such as expandablecasing liners and alternative borehole liners.

[0059] In FIG. 7A, the sand screen 100 has been run into the wellbore 40at the end of a working string 70. In this respect, the sand screen 100is releasably attached to an expander tool 200′. The expander tool 200′,in turn, is attached to the lower end of the working string 70. A linerhanger 140 is provided to hang the sand screen 100 once it is lowered tothe desired producing zone. A packer 150 is also shown. It isunderstood, of course, that other completion tools may be used, such asa run-in tool.

[0060]FIG. 7B presents the next step in the completion process. In FIG.7B, the liner hanger 140 and packer 150 have been set in the wellbore40. Axial stress has sheared the shear pins (not shown), releasing thecone 200′ from the top connector (shown as 110 in FIG. 6A). This allowsthe cone 200′ to move downward relative to the expandable tubular 100.The cone 200′ is moved downward at the lower end of the working string70. As the cone 200′ is urged downward, the expandable tubular 100 isradially expanded along its length. The tubular 100 is not expanded intocomplete frictional engagement with the surrounding formation 48, but anannular region is preserved. In the arrangement of FIG. 7B, a taperedcone is being used as the expander tool 200′. However, it is againunderstood that the methods of the present invention are not limited tothe manner in which expansion is accomplished, or the type of expandertool used.

[0061]FIG. 7C presents the next step in the completion process. Here,cement 55 is being injected through the working string 70, through theexpander tool 200′, and out of the mule shoe 180. The cement 55 is thensqueezed up the annular region defined by the sand screen 100 and thesurrounding formation wall 48. In this way, a thin tubular column ofcement 55 is placed in the open hole portion 50 of the wellbore 40.

[0062] It is noted that the sand screen 100 in FIG. 7C is held intension during the cementing and expansion process. However, the methodsof the present invention are not limited to an arrangement where thesand screen 100 (or other expandable tubular) is held in tension. It isunderstood that the expander tool, e.g., expansion cone, can be deployedin a position inverted from that shown in the drawings. In such anarrangement, the expander tool 200 is releasably attached to the sandscreen 100 (or some tool below the sand screen 100), and is then pulledupward through the sand screen 100 during the expansion process. Thesand screen 100 would then be expanded in compression against the hanger140 as the expander tool 200 is pulled upwards. Alternatively, theexpandable tubular 100 may be expanded in compression by resting thesand screen 100 on and against a cement shoe 180 or “mule shoe.” Themule shoe may be drillable and would be part of the deploymentequipment. No hanger would be required because the cement shoe 180 wouldbe resting on the bottom of the borehole. In this alternate arrangement,the cone 200 would again be releasably attached to the top connector 110(or otherwise above the sand screen 100), or form part of an expansionstring.

[0063] It should also be noted that the steps in FIGS. 7B and 7C may bereversed. In this respect, the cement 55 may be injected into theannular region before the tubular 100 is expanded. The expansionoperation is then conducted before the cement 55 has completely cured.Any cement deposited in the main bore of the sand screen 100 (or otherexpandable tubular) is then drilled out.

[0064]FIG. 7D demonstrates the optional step of drilling cement 55 outof the main bore of the sand screen 100. The sand screen 100 in itsexpanded state is shown in the view of FIG. 7D. The expander tool 200′(and run-in tool) has been removed from the wellbore 40, and the workingstring 70 has been reintroduced into the wellbore 40. A drill bit 75 isnow seen at the lower end of the working string 70. In the step of FIG.7D, the drill bit is drilling out cement 55 that is inside the sandscreen 100. A thin cement sheath 55′ is now left around the sand screen100.

[0065] Next, FIG. 7E presents the wellbore of FIG. 7A having beencompleted. The drill bit 75 has been removed from the wellbore 40, andfluids are being produced through the cement column 55 and through thesand screen 100. Arrows 15 depict the flow of fluids, such ashydrocarbons, into the wellbore 40.

[0066]FIGS. 8A-8E present steps for deploying a sand screen inaccordance with another of the methods of the present invention. In eachof these drawings, a cross-sectional view of a wellbore 40 is againseen. In this instance, the wellbore 40 is cased with a string ofcasing, such as a liner string 30.

[0067] In FIG. 8A, a liner string 30 is shown within the wellbore 40.The liner string 30 has been perforated. FIG. 8A could represent a newwellbore that is just being completed with new perforations 35;alternatively, it could represent an old well having perforated casingthat has corroded and is in need of support provided by a sand screen.

[0068]FIG. 8B demonstrates the sand screen 100 being run into thewellbore 40 of FIG. 8A at the end of a working string 70. The sandscreen 100 is temporarily connected to the working string 70 via arun-in tool (not shown). A packer 150 is positioned above the sandscreen 100. The sand screen 100 is releasably attached to an expandertool 200′, while the expander tool 200′, in turn, is attached to thelower end of the working string 70. The sand screen 100 is located at adepth that traverses the perforated zone of the liner string 30. In thearrangement of FIG. 8B, the sand screen 100 is simply landed on thebottom of the open borehole 50. A mule shoe 180 is shown resting at thebottom of the hole.

[0069]FIG. 8C presents the next step in the completion process. In FIG.8C, the packer 150 has been set in the wellbore 40. A liner hanger isnot needed in this arrangement, as the sand screen 100 is resting at thebottom of the hole. Axial stress has sheared the shear pins (not shown),releasing the cone 200′ from the top connector (shown as 110 in FIG.6A). This allows the cone 200′ to move downward relative to theexpandable tubular 100. The cone 200′ is moved downward at the lower endof the working string 70. As the cone 200′ is urged downward, theexpandable tubular 100 is radially expanded along its length. Thetubular 100 is not expanded into complete frictional engagement with thesurrounding formation 48, but an annular region is preserved. In thearrangement of FIG. 8C, a tapered cone is again being used as theexpander tool 200′. However, it is again understood that the methods ofthe present invention are not limited to the manner in which expansionis accomplished, or the type of expander tool used.

[0070]FIG. 8D presents the next step in the completion process. Here,cement 55 is being injected through the working string 70, through theexpander tool 200′, and out of the mule shoe 180. The cement 55 is thensqueezed up the annular region defined by the sand screen 100 and thesurrounding formation wall 48. In this way, a thin tubular column ofcement 55 is placed in the open hole portion 50 of the wellbore 40.

[0071] It is noted in the arrangement of FIG. 8D that the working string70 and the expander tool 200′ have been raised in the wellbore 40. Thisallows cement 55 to also fill all or a portion of the main bore of theexpandable tubular 100. In this respect, it is optional in the methodsof the present invention to place cement 55 not only in the annularregion outside of the sand screen 100, but also within the sand screen100 or other expandable tubular itself.

[0072] The sand screen 100 of FIG. 8B is shown in its expanded state inthe view of FIG. 8E. Here, the sand screen 100 has been expanded along adesired length. The expander tool 200 has been removed from the wellbore40, and the working string 70 has been reintroduced into the wellbore40. A drill bit 75 is now seen at the lower end of the working string70. In the step of FIG. 8E, the drill bit is drilling out at least aportion of the cement 55 that is inside the sand screen 100. A thincement sheath 55′ is now left around the sand screen 100.

[0073]FIG. 8F presents the wellbore 40 of FIG. 8B having been completed.The drill bit 75 is removed from the wellbore 40, and fluids are beingproduced through the cement column 55′ and through the sand screen 100.Arrows 15 depict the flow of fluids, such as hydrocarbons, into thewellbore 40.

[0074] In order for the methods shown in FIGS. 7A-7E, and FIGS. 8A-8F towork most effectively, it is desirable to provide cement 55 havingcharacteristics of increased permeability. The cement pore sizes should,after cure, be sized to prevent the formation sand grains from passingthrough under pressure, while still allowing the passage of fluids andclay (fines) particles. In this manner, the cement 55 aids in the sandfiltering process without preventing the flow of valuable hydrocarbonsinto the wellbore 40. An example is a hollow fiber cement, whichprovides small pore passages incorporated within the structure of thecement. The hollow fiber tubules also improve the structural integrityof the cement sheath. Alternatively, a permeable cement such as thatdescribed in U.S. Pat. Nos. 6,364,945 and 6,202,751, mentioned earlier,may be employed. The '945 and the '751 patents are incorporated hereinby reference, in their respective entireties.

[0075] When using a porous and permeable cement, the operator mayintroduce an acid to create interconnecting vugs and channels in thecement. This procedure is set out more fully in U.S. Pat. No. 6,390,195,mentioned earlier. The '195 patent is also incorporated herein byreference, in its entirety. In one aspect, the cement is comprised of ahydraulic cement, a particulate cross-linked gel containing an internalbreaker which after time causes said gel to break into a liquid, andwater present in an amount sufficient to form a slurry. After the cementhas been injected into the wellbore, and after it has been drilled outof the sand screen, the delayed internal breaker in the cement breaks.Acid is then introduced into the wellbore and through the sand screenwhere it comes into contact with the set cement. The acid dissolvesportions of the set cement composition connecting the channels thereinsuch that the set cement column 55′ is permeated substantially along itslength and width. The well is then ready for production, as shown inFIGS. 7E and 8F.

[0076] In one arrangement, the cement includes a particulate solid thatis soluble in the presence of a treating fluid, such as acid. The aciddissolves the particulate solids, thereby creating vugs and channelsthrough which hydrocarbons flow. In another aspect, the cementcomposition further comprises a gas present in an amount sufficient toform a foam, and a mixture of foaming and foam stabilizing surfactants.

[0077] Because the porous and permeable cement would introduce apressure drop into the completion, it is desirable that the thickness ofthe cement sheath be minimized. The use of an expandable tubular, suchas an expandable sand screen or slotted liner, allows the greatestpossible inflow area into the wellbore through the permeable cement,thereby minimizing cement thickness and pressure drop. In addition, theuse of an expandable tubular allows wells to be under-reamed, therebyallowing significant inflow advantages over conventional completiontechniques. Furthermore, since the tubular actually expands to an insidediameter greater than the maximum outside diameter of the expander tool,the final inside diameter of the tubular can be substantially equal tothat of the parent casing. This provides a larger filtering surfacearea, resulting in a lower pressure drop than using a conventional,non-expandable perforated pipe, and greater longevity due to the numberof pores available for flow. Further, the use of an expandable tubularto support the cement sheath 55′ provides additional security in case ofthermal or pressure related stress cracking to the cement 55′. Wellboresupport is provided even in extreme wash-outs and reactive shales. Thus,the above methods when used in cased and perforated wells are highlyerosion resistant as the sand grains are kept in place.

[0078] It should also be noted that the methods of the present inventionmay be used with a combination of permeable and non-permeable cement ina multi-stage cement job. In this respect, a producing zone can beisolated by cementing the annulus above and below the producing zonewith a non-permeable cement. A permeable cement can be squeezed into thearea adjacent the producing zone. The multi-stage cement job can be donein various steps—the order is not important for purposes of the presentinventions. By using normal cement and permeable cement in a multi-stagecement job coupled with the tubular mechanical support provided by theexpandable sand screen or tubular, a stable and effective sand controlmethod can be provided without gravel packing and perforatingoperations.

[0079] While the foregoing is directed to embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof. For example, a crossoverport and a cement shoe can be added to the deployment equipment. Thesand screen or tubular would be expanded after the cement is poured. Thecement would then be pumped through the expansion cone while it is onbottom and up through a preserved annulus between the sand screen andthe wall of the borehole. The cement would not pass through the sandscreen, so no drilling step would be required. The deployment equipmentis then retrieved, leaving a clean production bore.

1. A method for using an expandable tubular within a wellbore,comprising the steps of: running the tubular into the wellbore; locatingthe tubular in the wellbore adjacent a producing zone; expanding thetubular radially outward along a desired length; and placing cement inan annular region defined by the area between the expanded tubular andthe surrounding wellbore.
 2. The method of claim 1, wherein the wellborealong the producing zone is an open hole wellbore, allowing fluidcommunication between an earth formation at the producing zone and theexpanded tubular.
 3. The method of claim 1, wherein the wellbore alongthe producing zone is cased with a string of perforated casing, allowingfluid communication between an earth formation at the producing zone andthe expanded tubular.
 4. The method of claim 1, wherein the cement is apermeable and porous cement that permits fluids to flow from the earthformation to the expanded tubular.
 5. The method of claim 4, wherein themethod is conducted to remedy a failed completion.
 6. The method ofclaim 4, wherein the step of placing cement in the annular region isperformed by injecting cement through a tubular string, and then forcinga portion of the injected cement around the bottom of the expandedtubular and up into the annular region.
 7. The method of claim 4,further comprising the step of: removing substantially all of any cementdisposed within the expanded tubular, leaving a cylindrical cementcolumn in the annular region around the tubular.
 8. The method of claim7, wherein the step of removing substantially all of the cement disposedwithin the tubular is performed by drilling out the cement after it hassubstantially cured.
 9. The method of claim 4, wherein the tubular is anexpandable sand screen.
 10. The method of claim 9, further comprisingthe step of: injecting a treating fluid into and through the sand screenin order to contact and treat the cement column, the treating fluidincreasing the permeability of the set cement.
 11. The method of claim10, wherein the step of injecting the treating fluid is performed afterthe step of expanding the sand screen.
 12. The method of claim 4,wherein the cement is comprised of a hydraulic cement, a particulatecross-linked gel containing an internal breaker which after time causessaid gel to break into a liquid, and water present in an amountsufficient to form a slurry.
 13. The method of claim 12, furthercomprising the step of: injecting a treating fluid into and through thesand screen in order to contact and treat the cement column, thetreating fluid increasing the permeability of the set cement; andwherein the cement is further comprised of a particulate solid that issoluble in the presence of the treating fluid.
 14. The method of claim1, wherein the step of expanding the tubular is performed by using anexpander tool, the expander tool comprising a tapered cone portion urgedaxially within the tubular.
 15. The method of claim 14, wherein theexpander tool further comprises a hydraulically actuated tool portion.16. A method for forming a permeable cement sand barrier in a wellbore,the wellbore having a wall, the method comprising the steps of:deploying a perforated expandable tubular at a selected depth; expandingthe tubular; injecting a permeable cement composition into the annulusformed between the wall of the wellbore and the perforated expandabletubular; and allowing the cement composition to set.
 17. The method ofclaim 16, wherein the permeable cement defines a composition comprisedof: a hydraulic cement, a particulate cross-linked gel containing aninternal breaker which after time causes the gel to break into a liquid,allowing the particulate cross-linked gel containing the internalbreaker to break so that vugs and channels are formed in the cementcomposition as the cement composition sets; and water present in anamount sufficient to form a slurry.
 18. The method of claim 17, furthercomprising the step of: allowing the particulate cross-linked gelcontaining the internal breaker to break.
 19. The method of claim 18,wherein the cement composition further comprises an acid solubleparticulate solid; and the method further comprises the step ofintroducing an acid solvent into the perforated pipe whereby the acidsolvent flows through the perforations in the pipe and into contact withthe set cement composition so as to dissolve the acid solubleparticulate solid, thereby creating channels for the flow ofhydrocarbons therethrough.
 20. The method of claim 19, wherein thecement composition further comprises: a gas present in an amountsufficient to form a foam; and a mixture of foaming and foam stabilizingsurfactants.
 21. The method of claim 16, wherein the perforatedexpandable tubular is an expandable sand screen.
 22. A method for usingan expandable tubular within a wellbore, comprising the steps of:running the tubular into the wellbore; locating the tubular in thewellbore adjacent a producing zone; placing cement in an annular regiondefined by the area between the tubular and the surrounding wellbore;and expanding the tubular radially outward along a desired length beforethe cement has cured.
 23. The method of claim 22, wherein the expandabletubular is an expandable sand screen.
 24. The method of claim 22,further comprising the step of: hanging the expandable sand screenwithin the wellbore before the step of expanding the sand screenradially is conducted.